<!DOCTYPE html>
<html lang="en">

  <head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>原生animation的实现</title>
  </head>
  <style>
    .img {
      width: 100px
    }

    .enter {
      animation: enter 1s;
    }

    /* 
    关键帧
    */
    @keyframes enter {
      0% {
        transform: scale(0)
      }

      25% {
        transform: scale(1.1)
      }

      50% {
        transform: scale(1.2)
      }

      100% {
        transform: scale(1)
      }
    }
  </style>

  <body>
    <div>
      <button>切换</button>
      <img class="img enter" src="../img/shuai.jpg" alt="">
    </div>

  </body>
  <script>

  </script>

</html>